From FindLaw.com.
"A subpoena (pronounced "suh-pee-nuh") is a request for the production of documents, or a request to appear in court or other legal proceeding. It is court-ordered command that essentially requires you to do something, such as testify or present information that may help support the facts that are at issue in a pending case. The term "subpoena" literally means "under penalty". A person who receives a subpoena but does not comply with its terms may be subject to civil or criminal penalties, such as fines, jail time, or both.
There are two types of subpoenas. The first, called subpoena ad testificandum (pronounced "ad test- te-fi-kan-dum"), requires you to testify before a court, or other legal authority. The second, called subpoena duces tecum (pronounced "doo-seez tee-*advertiser censored*"), requires you to produce documents, materials, or other tangible evidence. A subpoena may be requested in any kind of matter, but the most common requests are from divorce, child custody, personal injury, and sex offender cases.
What Are Subpoenas Used For?
Under state and federal civil or criminal procedural laws, subpoenas offer attorneys a chance to obtain information to help prove or disprove their client's case. Criminal attorneys, for example, often use subpoenas to obtain "witness" or lay opinion testimony from a third party that may lead to someone's guilt or innocence at trial. Similarly, civil attorneys often subpoena individuals to obtain information that may help settle someone's claim. For example, an attorney representing a spouse in a child custody hearing might issue a subpoena to the other spouse to appear in court to determine joint custody arrangements.
Other examples of subpoenas may include requests for:
Blood test information;
DNA samples;
Computer files and downloaded material (such as in a child *advertiser censored* case, for example);
Medical bills & insurance records;
Income tax returns;
Photographs, graphs, & charts; and
Employee records.
- See more at:
http://litigation.findlaw.com/going-to-court/what-is-a-subpoena.html#sthash.g3N1VHy4.dpuf"